April1981 RAlN Page 21 expected to be more expensive. Heat pump water heaters are superb for commercial operations such as restaurants, light manufacturing, and office buildings that do generate waste heat. It is likely that in these situations heat pumps will prove superior to solar from both an energy and economics standpoint for most applications. Although residential applications are clearly more limited, there are many situations where a heat pump water heater makes sense. Furthermore, it is probable that they will soon be enjoying some of the same financial incentives as active solar systems, especially since utilities can relate to heat pumps a little more easily than they can to solar, and can be expected to be fairly enthusiastic about them. This raises the faScinating possibility that heat pump water heaters will be competing with active solar systems in many of the areas where solar works best. There are a couple of different systems available that integrate both heat pumps and solar, but fuel prices would have to go up quite a bit faster than they do now to justify the extra expense. Most people will be choosing between heat pumps and solar, and it is unlikely that the question of how the economics of solar and heat pumps compare over the long run will be settled for quite some time. Heat pump water heater manufacturers feel that there is no comparison. Their confidence is largely based on a 1978 report by Oak Ridge Laboratories that indicated, among other things, that heat pump water heaters would be able to offer comparable savings to active solar systems for about one-fourth to one-fifth the cost. The catch is that at the time the report was written, heat pump water heaters were expected to cost around $400. Actual retail prices are about twice that, and installed costs are running as high as $1500, with most installations falling in the $1000 to $1200 range. This is still about half the current installed cost of your average active solar system, and is considerably cheaper than the "Cadillac" solar systems that seem to be flooding the market lately. But it is not much cheaper than a well-designed, owner-installed system, and only time will tell which is the better investment. It may be that current claims of 50% energy savings from heat pump water heaters are low. They may also be high. If they are correct, a typical solar installation should be able to offer 20-50% greater savings (or a total savings of 60% to 75%) . In real life, however, solar systems have not always done as well as they are supposed to. If we assume that the relative savings are equal for both, the important question then becomes how long each system will last. If industry estimates of a IS-year lifespan for heat pump water heaters and a 30-year lifespan for active solar systems are correct, the total costs over a 3D-year period appear about equal. If either estimate is wrong, however, the advantage of the other system improves conSiderably. Many of the solar systems currently on the market are far more expensive and complicated than they need to be. Competition between heat pump and active solar water heaters could turn out to be very healthy, sparking a renewed interest in relatively simple, lowcost solar systems that is badly needed. Individually, heat pumps and active solar are clearly inappropriate for some installations, but there are few residential and commercial buildings that are not suitable for one or the other. Heat pump water heaters represent a potentially valuable addition to the array of energy conservation technologies available, and they should be welcomed as such. 00 Discussions and exhibits of systems and machines to process sludge, garbage and other organic wastes, as well as sessions on biogas and alcohol fuels will be featured at the 1981 Composting and Waste Recycling Conference to be held in Washington, D.C. May 18-20. To register or obtain additional information, contact Mildred Lalik, The JG Press, Box 351, Emmaus, PA 18049, 215/967-4135. An Underground Space Conference and Exposition will be held in Kansas City, JuneB-lO. The Utlent, to be sponsored by the American Undergrou nd-Space Association, will feature sessions by experts from around the world on earth-sheltered buildings, deep underground space use, urban planning and policy issues. Contact Ruth Sime, American Underground-Spac~ Association , c/o Suite 900, Minnesota Building, St. Paul, MN 5510I, 612/376-5580. The Farallones Institute Rural Center in Occidental, California announces a series of Community TechllOlogy Workshops on weatherization and conservation, July 20-31; solar home hearing, August 3-14; and solar water heating, August 17-28. The workshops are skills training programs, and are designed to address the particular needs of low-income and minority communities in both urban and rural areas. Financial aSSistance is available. Participants will live at the Center during the workshops. For further information contact Donna Clavaud, Farallones Rural CenttT, 15290 Coleman VaLIey Road, Occidental , CA A solar tour of England and France, August 22 to September 6, will be coordinated by Jordan College in co-sponsorship with Solar Age magazine and Mother Earth News. Contact Herbert Sebree, Tour Director, Jordan College, 360 W. Pine Street, Cedar Springs, MI "Energy and Big Building Design: Where We Are and Where We Are Going," a two-day statc-ofthe-art conference nn the design of internal loaddominated buildings, will be held in Philadelphia, May 25-26. The event, sponsored by the MidAtlantic Solar Energy Association, will be held in conjunction with the AS! ISES Solar Rising Conference (see announcement elsewhere this page). For details, contact Irisita Azary, Mid-Atlantic Solar Energy Association, 2233 Gray's Ferry Avenue, Philadelphia, PA 19146, 215/545-2150. @®rn~ooo
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